Pets that need to be walked are usually accompanied using leads equipped with a grip to be held by the user and a coupling element, generally the spring-clip type, which is attached to the pet's collar.
Some types of background art leads also foresee the use of a wind-up type cord which can be extended to allow sudden movements by the animal and also to give the pet greater freedom with a wider range of movement.
Winding devices for leads normally consist of a box-like body, provided with an anatomical grip, inside which is a wheel which can wind up the cord. The end of the cord or tape protrudes through an appropriate opening and is equipped with a spring clip which is attached to the pet's collar.
The tape which protrudes from the casing is short, that is to say the length of a normal lead, while the extensible cord attached to the tape can extend for several metres when unwound, then rewinding automatically by intervention of an internal steel mechanism.
The retractable tape can easily be blocked by means of the temporary block or fixed block, by slightly pressing the pushbutton which acts as a stop element or brake of the winding device.
There are numerous different means currently in use which block the winding device partially or completely.
For temporary blocking it is sufficient to press the pushbutton, so that the brake blocks the winding device for as long as the pushbutton is held down, preventing the pet from moving away.
In some cases, in addition to the temporary block pushbutton, useful for example when the dog should walk in step with the user, there is also a safety pushbutton which blocks the lead even when the temporary pushbutton is released, allowing the lead to remain at a fixed length.
The safety pushbutton on traditional lead winding devices presents a series of problems, however, making it difficult to use since it is usually positioned beside the temporary pushbutton. It also involves construction problems due to the presence of auxiliary mechanical components alongside the main mechanical device.